This invention relates to an improved safety device for lever operated chain hoists and other winches and is herein illustratively described by reference to its presently preferred embodiment. However, it will be recognized that certain modifications and changes therein will respect to details may be made without departing from the essential features involved.
In the interests of safety, lever operated hoists and winches are being equipped increasingly with articulated type operating levers with overload indicators that operate in response to the application of excessive force to the operating lever. When this occurs the outer member of the operating lever pivotally connected to the winch-mounted inner member thereof overcomes the resistance of an overload spring that normally holds the members in operating alignment. Yielding of the overload spring permits the outer member to shift through a small acute angle into an opposite limit position relative to the inner member. Such relative breaking movement between the lever members also operates an overload indicator such as a device that shows green in a viewing window when the lever members are in normal operating alignment and red when they are in the broken or overload responding relationship. In the past, a winch operator, negligent about safe operating limits of the winch, with very little added effort could quickly force the lever members back into their normal operating alignment and thereby escape notice by a safety inspector or job superintendent. As a consequence, and with little effort or delay required to reset the conventional overload handle, there was relatively little deterrent to improper usage of the equipment.
A broad object of the present invention is to provide a relatively inexpensive, effective and reliable lockout device that responds automatically to overload beak motion between the lever members so as to prevent resetting of the same and removing the overload indication until the winch operator has first manually reset the lockout device itself. A related object is to devise such a resettable safety lockout means for use in winches of this type that can be reset only upon certain deliberate operations that require actions not readily hidden or masked from observation by others, and in fact that are not overly simple, as a means to discourage repeated offenses in the misuse of the equipment.
A further object hereof is to devise such a resettable safety lockout means that is readily incorporated in commercially available types of safety overload indicating winch levers without adding materially to the weight or cost thereof.